Reaction #56585

Reaction equation

hydrochloric acid

1,3-dicyclohexylcarbodiimide

linoleic acid

metronidazole

→

2-(2-methyl-5-nitroimidazolyl)ethyl-z,z-octadeca-9,12-dienoate

Solvents

dichloromethane

Conditions

Workup

1. 1
   workup.STIRRINGstirring
2. 2
   FiltrationAfter filtration the organic layer
3. 3
   Otherwas separated
4. 4
   Washwashed with 50% saturated brine and finally with saturated aqueous sodium bicarbonate
5. 5
   DryingThe dichloromethane solution was dried (sodium sulfate)
6. 6
   Otherevaporated in vacuo (30° C./20 mm Hg)
7. 7
   workup.ADDITIONTo the resulting residue was added petrol (bp 30-60° C., 20 ml)
8. 8
   workup.WAITto stand at room temperature for 2 hours
9. 9
   Otherthe precipitation of the remaining urea
10. 10
    OtherThis was removed by filtration

Procedure

To a suspension of metronidazole (1.9 g) in dry dichloromethane (20 ml) was added successively 4-(N,N-dimethylamino)pyridine (1.22 g), 1,3-dicyclohexylcarbodiimide (2.2 g) and linoleic acid (2.8 g). The mixture was stirred at room temperature overnight. To the reaction was added 2M hydrochloric acid (20 ml) and stirring was continued. After filtration the organic layer was separated, washed with 50% saturated brine and finally with saturated aqueous sodium bicarbonate. The dichloromethane solution was dried (sodium sulfate) and evaporated in vacuo (30° C./20 mm Hg). To the resulting residue was added petrol (bp 30-60° C., 20 ml) and the mixture allowed to stand at room temperature for 2 hours, causing the precipitation of the remaining urea. This was removed by filtration and the filtrate was applied to a dry column giving 2-(2-methyl-5-nitroimidazolyl)ethyl-z,z-octadeca-9,12-dienoate as a pale yellow, non distillable oil.

Source